1. Field of the Invention
The present invention relates to a fuel tank mounted on an apparatus that carries an engine thereon, such as an engine generator and a general-purpose engine.
2. Description of the Related Art
An example of a conventional fuel tank mounted on a general-purpose engine is described in Japanese Publication No. JP-2005-163688. Such a fuel tank includes a tank body for storing fuel therein, a fuel inlet provided on a top face of the tank body and projecting upwardly therefrom, and a fuel cap removably installed on the fuel inlet.
As apparent from FIG. 6 of JP-2005-163688, a fuel tank 48 according to JP-2005-163688 is disadvantageous in that, with the fuel tank 48 that includes a groove 79 having a relatively-large cross-sectional area to bring an evaporative fuel passage 78 into communication with the fuel tank 48, if fuel is accidentally oversupplied to reach an upper end of the fuel inlet, air in the fuel tank 48 at a portion radially outward from a seal support 59 easily escapes through the groove 79 to the outside of the fuel tank 48. Accordingly, the fuel remains filled to the upper end, and hence a liquid level of the fuel in the fuel inlet does not decline.
In contrast, when the fuel tank 48 includes the groove 79 having a relatively-small cross-sectional area, if fuel is accidentally supplied to the upper end of the fuel inlet, air less easily flows out through the groove 79. More specifically, because a channel in the groove 79 extends horizontally, a buoyant force urges bubbles generated from the fuel and air in the fuel tank 48 to move upward. Hence, the bubbles remain clogged in the groove 79 and less easily escape out through the groove 79. Consequently, air is trapped in the fuel tank 48 and the liquid level of the portion radially outward from the seal support 59 does not rise to be higher than a lower end of the seal support 59. Hence, the liquid level of the fuel in the fuel inlet does not decline.
As described above, in either case in which the groove 79 is large or small in cross-sectional area, fuel can flow into a canister through piping provided for guiding evaporative fuel vapor produced in the fuel tank to the canister, thereby functionally damaging the canister.